Remove unit test based on now incorrect assumptions

src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -996,7 +996,7 @@ public class CraftEventFactory {
     }
 
     public static PrepareAnvilEvent callPrepareAnvilEvent(InventoryView view, ItemStack item) {
-        PrepareAnvilEvent event = new PrepareAnvilEvent(view, CraftItemStack.asCraftMirror(item).clone());
+        PrepareAnvilEvent event = new PrepareAnvilEvent(view, CraftItemStack.asCraftMirror(item));
         event.getView().getPlayer().getServer().getPluginManager().callEvent(event);
         event.getInventory().setItem(2, event.getResult());
         return event;
@@ -1016,7 +1016,7 @@ public class CraftEventFactory {
 
     public static EntityBreedEvent callEntityBreedEvent(EntityLiving child, EntityLiving mother, EntityLiving father, EntityLiving breeder, ItemStack bredWith, int experience) {
         org.bukkit.entity.LivingEntity breederEntity = (LivingEntity)(breeder == null ? null : breeder.getBukkitEntity());
-        CraftItemStack bredWithStack = (bredWith.isEmpty()) ? null : CraftItemStack.asCraftMirror(bredWith).clone();
+        CraftItemStack bredWithStack = CraftItemStack.asCraftMirror(bredWith);
 
         EntityBreedEvent event = new EntityBreedEvent((LivingEntity) child.getBukkitEntity(), (LivingEntity) mother.getBukkitEntity(), (LivingEntity) father.getBukkitEntity(), breederEntity, bredWithStack, experience);
         child.world.getServer().getPluginManager().callEvent(event);

src/test/java/org/bukkit/craftbukkit/inventory/NMSCraftItemStackTest.java

@@ -25,12 +25,4 @@ public class NMSCraftItemStackTest extends AbstractTestingBase {
         assertThat(clone.getData(), is(itemStack.getData()));
         assertThat(clone, is(itemStack));
     }
-
-    @Test
-    public void testCloneNullItem() throws Exception {
-        net.minecraft.server.ItemStack nmsItemStack = null;
-        ItemStack itemStack = CraftItemStack.asCraftMirror(nmsItemStack);
-        ItemStack clone = itemStack.clone();
-        assertThat(clone, is(itemStack));
-    }
 }